The present invention relates to sensor systems employed for determining actuation of safety restraints in a vehicle and more particularly for sensor systems that detect possible rollover conditions of a vehicle.
Conventional passive restraints systems are generally configured with a sensor system set up to detect frontal collisions of a vehicle and actuate passive restraints to better protect the occupants. More recently, the sensor systems are set up to also detect certain side impact situations and the passive restraints are configured to protect passengers for these side impact situations as well. For the frontal impacts, a common sensing system includes a single point impact sensor that is mounted near the center of the vehicle and oriented to detect fore-aft (longitudinal) acceleration of the vehicle, and employs this signal to determine when and which passive restraints to actuate. These may be, for example, front airbags or seat belt pretensioners.
Additionally, in order to now detect side impacts of the vehicle, some sensor systems employ side satellite sensors that are oriented to detect side-to-side (lateral) acceleration of the vehicle. These side satellite sensors are typically mounted in or near the side doors of the vehicle to obtain an earlier detection of a side impact than a centrally mounted acceleration sensor might. These side satellite sensors are then electrically connected to a restraints control module, along with the single point impact sensor. This necessitates separate housings and wiring for each of the satellite sensors, with the associated costs and packaging concerns.
An additional type of sensing for vehicle passive restraint actuation is now becoming more desirable, rollover detection. A roll rate sensor, unlike typical frontal and side impact sensors, measures a vehicle""s angular position with respect to the ground or the rate of change in angular position over time. By measuring one of these types of physical parameters, passive restraints may be deployed specifically to provide protection for vehicle occupants under certain vehicle rollover conditions. The typical accelerometers employed for frontal and side impacts are generally not suitable for such use; even if oriented properly, the output needs to be subjected to exhaustive calculations before actuation decisions can be made. On the other hand, by adding a separate roll rate sensor, packaging and wiring for this additional sensor is now a concern in addition to the cost.
In its embodiments, the present invention contemplates a sensor system for use with passive restraints in a vehicle having a longitudinally directed vehicle centerline. The sensor system includes a longitudinal impact sensor located generally adjacent the longitudinally directed vehicle center line, and a restraints control module in communication with the longitudinal impact sensor. A first satellite sensor housing is mounted in the vehicle spaced from the restraints control module, and a lateral impact sensor is mounted in the satellite sensor housing and in communication with the restraints control module via a first communication link. The sensor system also includes a roll rate sensor mounted in the satellite sensor housing and in communication with the restraints control module via the first communication link.
Accordingly, an object of the present invention is to provide a passive restraint sensing system that includes both frontal impact sensors located near or in a main restraints control module as well as side satellite sensor housings that also incorporate a rollover detection sensor.
An advantage of the present invention is that the rollover sensor is incorporated into a side satellite sensor housing, minimizing the need for extra wiring and packaging another housing, thus reducing the cost of the overall sensor system.
Another advantage of the present invention is that the cost and complexity of the sensor system is reduced, while still providing the additional function of vehicle rollover detection.